HODEIDAH, NORTH YEMEN, DEC. 10 -- President Ali Abdullah Saleh said today that he will be seeking improved "special" relationships with both the United States and the Soviet Union to help maintain the economic and military security of the lower Arabian peninsula.

Saleh, who has not visited the United States since coming to power in 1978, said he has accepted an invitation to Washington extended after Vice President George Bush's visit here last year.

But western diplomatic sources said it is more likely that Saleh will visit Moscow early next year in recognition of a large Soviet military aid program, which has been accelerated over the last 12 months.

A date for a U.S. visit has not been set.

Speaking to four western journalists at his presidential compound in this Red Sea port, Saleh asserted that his continuing discussions with Marxist South Yemen on a reunification accord do "not pose any danger" to regional stability.

He reaffirmed his policy of nonalignment between the superpowers, which have courted North Yemen as a potential strategic outpost overlooking the Red Sea shipping and oil routes to the Suez Canal and the West.

The Soviet Union already maintains naval facilities near the entrance to the Red Sea at the South Yemeni port of Aden and on Socotra Island in the Bab al Mandab Strait.

These outposts have given Soviet warships more flexibility to increase their naval presence in the Persian Gulf.

In the interview, Saleh avoided criticizing U.S. or Soviet policy in the Middle East, though his government has complained privately about a range of U.S. policies, including arms sales to Iran and American reliance on Saudi Arabia to manage U.S. arms supplies to North Yemen.

North Yemen is a strong supporter of the Iraqi war effort and has sent an estimated 3,000 combat troops to aid the Baghdad government, the only Arab country to do so.

Saleh, 42, who has brought nine years of relative stability to his country after two of his predecessors were assassinated, turned two pipeline valves at an oil terminal just north of here this week to inaugurate this impoverished nation's first flow of crude oil.

The oil will bring an estimated $600 million in new revenue to North Yemen in 1988.

But as Foreign Minister Abdul Karim Eryani told reporters at an earlier news conference, the new oil revenues will do little more than replace earnings the government has lost from the return of expatriate workers sent to the gulf Arab states during the oil boom of the last decade.

In addition, North Yemen's oil is entering the market at a time when oil prices are teetering at the $18-a-barrel level set last year by the Organization of Petroleum Exporting Countries, some of whose members have disregarded production quotas designed to hold prices firm.

Still, the Alif and Azal fields in North Yemen's eastern desert have been described by oil industry officials as an impressive discovery.

They comprise 500 million barrels in proven reserves that will allow the country to pump up to 200,000 barrels a day of crude oil through a 260-mile pipeline that crosses the country to the Red Sea.

Texas oilman Ray L. Hunt, chairman of the Dallas-based Hunt Oil Co., which struck oil in North Yemen with its first well in July 1984, said the reserve figure could go much higher as his firm, joined by Exxon Corp. and a Korean oil company, continues its exploration in the northeastern and western offshore areas of the country.

Western diplomats credit Saleh's longevity in office to his shrewd political instincts in holding together North Yemen's tribal-based social structure, where rural sheiks still preside over heavily armed and highly territorial clans that traditionally have resisted control from any central government.

"Most people were giving odds that he wouldn't last a a year when he took office," said one western diplomat.

But Saleh has demonstrated an ability to bring the country's tribes into a loose confederation giving them a consultative role in government policy making and development planning.

"This is not an authoritarian dictatorship," Saleh said, speaking through an interpreter.

"We have come to the conclusion that democracy is the only thing to have in Yemen. Maybe it is not the same as in the United States or Western Europe, but we have our own processes . . . inherited from the past and our reference is history."

Nevertheless, Saleh's military and security apparatus maintains tight control over the country, where roads are studded with police checkpoints and garrison military forces cut a high profile in the towns and cities.

"This is a violent people," one western official said. "Mountain people are fiercely independent and Yemen is no exception.

"The north is extremely tribal and no government can hope to rule by brute force, so Saleh really had no choice but to be a leader who consults, who mediates. He wouldn't have lasted this long if he hadn't."

North Yemen, though closely allied with Saudi Arabia, which finances most of the U.S. military aid that reaches here, still has unresolved border disputes with its northern neighbor.

Western diplomats say the Saudis, ever mindful that North Yemen's population of 8 million is the largest on the peninsula, still finances northern tribesmen as a potential trouble-making lever against the central government in Sanaa.

To offset his dependence on Saudi aid, Saleh maintains his strong military supply relationship with the Soviet Union, western officials said, as well as his courtship with the Marxist regime in Aden to the south.

North Yemen's interest in reunification with the South has been a source of continuing concern in Washington and in staunchly anticommunist Saudi Arabia, whose leaders are said to be deeply alarmed at the rise of Soviet-backed governments on their southern flank in Ethiopia and South Yemen.

Saleh acknowledged in the interview that he is providing refuge to former South Yemeni president Ali Nasser Mohammed, who fled South Yemen early last year after a bloody clash between Marxist factions in the government.

South Yemen similarly harbors leftist opponents of Saleh's regime who fought alongside South Yemeni troops during a 1979 border war.

"Each side knows the other could accelerate the hostilities at any time by sending a group of well-armed people against the other," one western official said.